STUDY ON COUNTERMEASURES TO REDUCE IMPULSIVE FORCES ACTING ON TSUNAMI SEAWALL

Abstract

 Tsunami wave forces acting on seawall are divided into the impulsive forces and the hydrostatic forces, and the evaluation method of the impulsive forces has not been established. If the impulsive forces can be reduced less than the hydrostatic force, the hydrostatic force becomes dominant in tsunami force. In this study, the countermeasure to reduce impulsive forces was proposed, and its effect was confirmed by hydraulic experiments and numerical simulations. It was found that the impulsive force caused by falling to the water surface is reduced because the run-up water is dispersed by the countermeasures, and therefore the countermeasures work effectively. On the other hand, the length and shape of the countermeasure should be properly determined in consideration of the tsunami wave form and the scale of the tsunami run-up.